The current global—and Congressional—debate about whether to deploy force against Syria for its use of sarin gas on civilians will depend, in part, on whether the reasons for a post-World War I agreement banning the offensive use of chemical and biological weapons continue to be honored.
The 1925 Geneva Protocol did not focus on World War I's terrible new 20th-century technologies that made 19th-century military tactics obsolete and led to mass slaughter: advancements in barbed wire, machine guns, and artillery led to incomprehensible and horrible effects on combatants. It was the impact of gas use on both the Western and Eastern fronts that led to the prohibition on chemical and biological warfare, even though it had led to only about one percent of the deaths there. The protocol viewed gas warfare as different from the other methods of mass killing, and banned the use of "asphyxiating, poisonous or other gases" as well as "bacteriological methods."
At least three strains of reasoning were advanced by the International Red Cross, religious leaders, the military, and politicians to help mobilize public opinion in favor of a special prohibition against chemical and biological warfare.
First, there were the unique methods of killing—and the special suffering—caused by the gases of World War I, which were first used by the Germans in the battle of Ypres in 1915 and then by all the armies. Chlorine damaged ears and eyes and caused death by asphyxiation. It was subsequently replaced by phosgene, a colorless gas that damaged the lungs and caused suffocation in a delayed reaction after exposure. Mustard gas caused blistering of the outer body and internal organs, especially the lungs. Death might come only after prolonged agony. And those who survived often had serious respiratory and other health issues for the rest of their lives.
Second, there was the "indiscriminate" impact of gas warfare. It was diffused broadly in the atmosphere—and could blow back into the offensive users or affect civilian populations. This uncontrolled aspect of gas warfare led to opposition among some military leaders on all sides.
Finally, there was a fear of an unknown future. Despite the relatively small number of actual deaths and casualties from chemical warfare compared to the horrific total, there was worry about its much broader use in the future. The inhuman, terrifying images of soldiers in gas masks fed these emotional concerns.
Together, these reasons led to a special strain of public fear and loathing that prompted the collective action embodied in the 1925 protocol. It stated that such warfare "has been justly condemned by the general opinion of the civilized world." Forty nations originally agreed to the protocol. Today that number is more than 130—although the United States did not officially adopt the protocol until 1975. And Syria adopted it in 1968.